Methods for the production of polyolefins with end-functionalized groups are typically multi-step processes that often create unwanted by-products and waste of reactants and energy. For reviews of methods to form end-functionalized polyolefins, see: (a) S. B. Amin and T. J. Marks Angew. Chem. Int. Ed. 2008, 47, 2006-2025; (b) T. C. Chung Prog. Polym. Sci. 2002, 27, 39-85; (c) R. G. Lopez, F. D'Agosto, C. Boisson Prog. Polym. Sci. 2007, 32, 419-454. A process with a reduced number of steps, even one step, would be desirable.
U.S. Pat. No. 4,110,377 discloses secondary aliphatic amines alkylated with alpha-olefins, such as ethylene, propylene, hexene, and undecene. Likewise, several literature references disclose hydroaminoalkylation of olefins using various catalysts (see J. Am. Chem. Soc. 2008, 130, 14940-14941; J. Am. Chem. Soc. 2007, 129, 6690-6691; Angew. Chem. Int. Ed. 2009, 48, 8361-8365; Angew. Chem. Int. Ed. 2009, 48, 4892-4894; Yuki Gosei Kagaku Kyokaishi (2009), 67(8), 843-844; Angewandte Chemie, International Edition (2009), 48(6), 1153-1156; Tetrahedron Letters (2003), 44(8), 1679-1683; Synthesis (1980), (4), 305-306). Corey discloses low molecular weight olefins treated with hydrosilanes in the presence of Cp2MCl2 and n-BuLi to prepare low molecular weight hydrosilylated products.
None of the above references however disclose functionalization of polyolefins, particularly polyolefins having Mn's over 200 g/mol, more particularly over 500 g/mol having large amounts of vinyl terminal groups.
U.S. Ser. No. 12/487,739, filed Jun. 19, 2009 discloses certain vinyl terminated oligomers and polymers that are functionalized for use in lubricant applications.
U.S. Ser. No. 12/143,663, filed on Jun. 20, 2008 discloses certain vinyl terminated oligomers and polymers that are functionalized in U.S. Ser. No. 12/487,739, filed Jun. 19, 2009.
U.S. Ser. No. 12/488,093, filed Jun. 19, 2009 discloses a process to functionalize propylene homo- or co-oligomer comprising contacting an alkene metathesis catalyst with a heteroatom containing alkene and a propylene homo- or co-oligomer having terminal unsaturation.
None of the above references however disclose functionalization of polyolefins, particularly polyolefins having Mn's over 500 g/mol having large amounts of vinyl terminal groups.
End-functionalized polyolefins that feature a chemically reactive or polar end group are of interest for use in a broad range of applications as compatibilizers, tie-layer modifiers, surfactants, and surface modifiers.
Thus, there is a need to develop a means to provide functionalized polyolefins (particularly end-functionalized) by efficient reactions, particularly reactions with good conversion, preferably under mild reaction conditions with a minimal number of steps, preferably one or two steps.
The instant invention's use of transition metal catalysts, such as metallocenes, to introduce hydrosilane groups is both a commercially economical and an “atom-economical” route to end functionalized polyolefins. Herein is described a novel method for their production by the reaction of vinyl-terminated polyolefins with hydrosilanes in the presence of a metallocene catalyst. This method is useful for a range of vinyl terminated polyolefins, including isotactic polypropylene (iPP), atactic polypropylene (aPP), ethylene propylene copolymer (EP), and polyethylene (PE).